1. Field
The described technology generally relates to an active cell balancing circuit and a cell balancing method using the same.
2. Description of the Related Technology
Studies on rechargeable batteries have been actively conducted with the development of portable electronic devices such as a cellular phone and a notebook computer. Particularly, various kinds of secondary batteries have been developed, such as a nickel-cadmium battery, a lead storage battery, a nickel metal hydride (NiMH) battery, a lithium polymer battery, a metal lithium battery and a zinc-air storage battery. Such a secondary battery is generally combined with a circuit so as to constitute a battery pack, and charging and discharging are performed through an external terminal of the battery pack.
A battery pack generally includes battery cells and a peripheral circuit having a charging/discharging circuit. The peripheral circuit is generally manufactured as a printed circuit board and then coupled to the battery cells. If an external power source is connected to the battery pack through an external terminal of the battery pack, the battery cells are charged by external power supplied through the external terminal and the charging/discharging circuit. If a load is connected to the battery pack through the external terminal, the operation is performed, in which the power of the battery cells is supplied to the load through the charging/discharging circuit and the external terminal. In this case, the charging/discharging circuit controls the charging/discharging of the battery cells between the external terminal and the battery cell. Generally, a plurality of battery cells are connected in series and parallel so as to be suitable for the consumption capacity of the load.